Not since World War Two has the nature and adequacy of international law provoked such a debate, both in Britain and abroad. A great number of international agreements have been adopted over the past sixty years, establishing minimum standards of behaviour with which states and other international actors must undertake to comply. They affect people in every country, and cover just about every subject: trade, investment, air transport, oceans, boundaries, environment, human rights, armed conflict. The great majority of these rules are not controversial; they work efficiently, and they are complied with. They establish the minimum standards necessary for co-operation in an increasingly interdependent world. The emergence of this great body of rules reflects a silent global revolution. But most people are unaware of the rules, of how they are made, and of quite how many of them there are, and this raises serious concerns about the accountability and legitimacy of international law-making. In Britain, almost all treaties are rubber-stamped by the executive and are not debated or even properly noted by Parliament, unless they address an issue of EU law. In the United States, there is an appropriately lively and informed debate about international law-making, democracy and constitutionalism. Jack Goldsmith and Eric Posner, the authors of The Limits of International Law, have contributed significantly to that debate and have played an important role in focusing attention on issues of legitimate concern. A similar debate is needed in Britain, as an increasing number of national laws are adopted off the back of international norms which have often been negotiated by the executive in circumstances in which the legislature plays no role.

It is also important to be clear about the limited function of global rules, especially those that impinge most directly on the exercise of sovereignty on issues affecting the vital interests of states, such as the security of citizens and the circumstances in which force can be used. Global rules clearly cannot sort out all the wrongs of the world. A great many of them need attention, not least as a result of the changes that have taken place since the 1940s. The number of states has increased from around fifty to around two hundred, as a consequence of decolonisation. The number of issues on which international co-operation and international legislation are required has grown exponentially. New actors have emerged: the importance of international organisations, NGOs and corporations pose challenges to an international legal order constructed on the assumption that the global order revolved around states. Failed states, the movement of people between states, permeable national borders, malign non-governmental forces such as al-Qaida, and the proliferation of weapons of mass destruction – all these pose further challenges.

Why do states comply with international law? That important question lies at the heart of The Limits of International Law. Goldsmith and Posner are well-known sceptics about the efficacy of international rules and the legitimacy of the international law project that began after World War Two. Their book’s chief value is that it sheds light on the intellectual foundations of the assault on global rules led by the Bush administration. Goldsmith joined the administration in 2002, first in the general counsel’s office at the Pentagon and then as assistant attorney general in the Office of Legal Counsel, which he left in June 2004.

Goldsmith and Posner are clear that ‘the best explanation for when and why states comply with international law is not that states have internalised international law, or have a habit of complying with it . . . but simply that states act out of self-interest.’ This assumes that states can and do act rationally, and that in exercising rational choices the values they apply are consistent with those of Goldsmith and Posner. Practice suggests otherwise. The authors’ claim is difficult to sustain even on the basis of the limited material they deal with.

My own experience has been that states comply with international laws for a variety of different reasons at different times in relation to different subjects. The reasons for compliance are not always clear or consistent, but in the vast majority of cases states do not comply merely on the basis of immediate or direct political self-interest. The obligations of international law have, to a large extent, been internalised. Sometimes a state complies because a legal adviser tells it to; occasionally because an international court has told it to; and more frequently because one of its own courts has told it to (as in the case of the foreign detainees held at Belmarsh, whose indefinite detention was ruled to be unlawful by reference to the United Kingdom’s international obligations, among other rules). Sometimes a state complies because another state has told it to. Sometimes a state doesn’t comply until the opprobrium and political consequences of not doing so become so great that domestic political processes compel it to change its stance (as in the case of the legislative amendment proposed by John McCain and adopted by the US Senate, which caused the Bush administration to change its actions and commit more clearly to international obligations placing limits on the interrogation of detainees).

Goldsmith and Posner do not discuss any of this. Their simplistic approach, which appears wilfully disconnected from reality or experience (a week working in a government legal adviser’s office in London, Tirana or Kinshasa would provide a rather different perspective), is bound to raise suspicion that they are motivated by the overriding political consideration of confirming the irrelevance of international law as law. The assumptions they apply are telling, as are those they exclude. They tell us that they ‘consistently exclude one preference from the state’s interest calculation: a preference for complying with international law’. Their rationale is that ‘it is unenlightening to explain international law compliance in terms of a preference for complying with international law. Such an assumption says nothing interesting about when and why states act consistently with international law.’ In my experience it is this very assumption – often unstated – that drives most states to comply with most of their international obligations most of the time. It is precisely a process of internalisation that causes states to put into effect new international regulations on aircraft emissions, for example, without asking themselves whether this would be justified by self-interest. In this sense, however, it borders on the naive to treat as equivalent the rules on aircraft emissions and rules on the use of force.

Equally misconceived is the apparent assumption that all states approach such matters in the same way. Plainly, that is not right. States are different, and they function differently, according to the personalities of individual ministers, the structure of government, and the value system and weight of values given to particular objectives. Two equivalently small and weak states may decide to comply with a particular international treaty obligation – or not – for entirely different reasons. Powerful states may also react differently. Look at the varying ways the US, Spain and the UK have dealt with their international obligations – the obligations in relation to human rights legislation in particular – following the large-scale terrorist attacks in those countries.

Goldsmith and Posner seem to assume that the state is an autonomous and unified entity, when in fact different branches of government see international rules in different ways. In Britain, after the July 2005 bombings, the executive took one view as to what compliance with international rules meant, and the courts took a rather different one. So far the courts have prevailed. Goldsmith and Posner have nothing to say about the role of the courts, or about the consequences of the absence of such courts in other states. That is a major omission.

The ‘life of law has not been logic’, Oliver Wendell Holmes said. ‘It has been experience.’ As a member of Bush’s administration, Goldsmith would have seen first-hand how it took decisions on the US’s international obligations. Unfortunately he does not draw directly on those experiences. It would be interesting to know, for example, the circumstances in which he wrote a draft legal opinion on 19 March 2004 on the meaning of Article 49 of the Fourth Geneva Convention. Article 49 states clearly that ‘individual . . . transfers . . . of protected persons from occupied territory to the territory of the occupying power or to that of any other country, occupied or not, are prohibited, regardless of their motive.’ Despite this, Goldsmith managed to conclude that Article 49 allowed overseas transfer of certain persons for a brief but not indefinite period to facilitate interrogation. In my view that conclusion is wrong. But the point of interest here is that the draft opinion does not anywhere indicate that the US is entitled to dispense with accepted interpretations of Article 49 for reasons of self-interest. The draft opinion is prepared as though there is such a thing as international law with which the US is bound to comply.

It is curious that the book steers well clear of examples dealing with international humanitarian law, including the rules governing the treatment of detainees during times of armed conflict. Equally curious is the decision to ignore the experience of the European Union. It is difficult to think of a better example with which to explore questions of compliance than the EU, built as it is on a set of treaties with which the record of compliance, over nearly fifty years, has been remarkable. Yet Goldsmith and Posner write off the ‘remarkable EU human rights phenomenon’ as ‘part of political and economic co-operation among states that are unifying into a larger state’. Putting aside the evident confusion between the Council of Europe and the EU, the claim that the EU is about to morph into a single state is wrong both factually and legally. Equally telling is the claim that the World Trade Organisation’s dispute settlement mechanism introduced ‘only modest reforms’ to the rules of the General Agreement on Tariffs and Trade. This reflects a serious lack of understanding of what states agreed when they created the WTO in 1994 (led by the US). The new WTO rules provide for binding dispute settlement, whereas the old GATT mechanism was non-binding. That is a major change, obviously relevant to issues of compliance.

Michael Byers’s War Law focuses on the two general sets of rules relating to the use of force: those governing the circumstances in which military force may be used (the jus ad bellum), and those governing the methods and means of warfare (the jus in bello). The events of 9/11 focused attention on the adequacy of the rules governing the right to use force to protect fundamental human rights, to address global terrorism and to snuff out existing (or emerging) threats posed by weapons of mass destruction. The actions of the US and some of its allies since 9/11 have put Guantánamo, Abu Ghraib and Bagram on the front pages, together with some important questions concerning the rules governing the interrogation and treatment of detainees. Byers deals with all of this, ranging from the circumstances in which self-defence may be used (including pre-emptively) to the arguments for and against unilateral humanitarian intervention (unauthorised by Security Council resolution) or intervention to protect democratic principles, as well as a range of issues concerning international humanitarian law and the emergence of international criminal law and tribunals. Much of the book focuses on US actions under Bush; it pays less attention to the positive role the US has played since World War Two in the creation of the rules he discusses.

Byers, an unabashed believer in the project of international law, is alert to the political context in which it inevitably has to be interpreted and applied. Yet as far as I can tell, he seems not to have decided if the existing rules are adequate, or whether they should be seen either through a traditional prism or in the light of the new paradigms that some people say have emerged. This is apparent, for example, in his approach to the legality of recent armed conflicts. He concludes that Nato’s use of force in Kosovo was inconsistent with international law, but doesn’t reach a similarly clear conclusion regarding the US-led war against Iraq in March 2003. Byers sees ‘some support’ for the argument that the war could be justified on the basis of the 1990 Security Council authorisation of the first Iraq war. This conclusion is essentially based on the idea of ‘implied authorisation’: in other words, the Security Council can give the green light to use force without making an express decision. But there is no real support for this, and for good reason: the present situation with Iran makes it clear that any hint of such a concept would make it virtually impossible for the Security Council to act at all.

Byers’s reasoning on this argument and on the facts of Iraq is not persuasive:

The members of the UN Security Council had agreed to disagree when, in November 2002, they adopted Resolution 1441. Different provisions of that resolution provide support to both sides of the debate over the legality of going to war against Iraq. By carefully balancing the arguments, the Security Council succeeded in effectively de-legalising the situation, and thus protecting the international legal system from the damage that would otherwise have resulted when politics prevailed.

It is not clear to me what he means by ‘de-legalising’ a situation. Does he mean that the Security Council consciously (or otherwise) found the issue to be entirely outside the scope of the existing and applicable rules of international law? On Byers’s own approach that can’t be right. At the very start of his book, for example, he asserts that ‘the question is not whether international law exists, but how and when it matters.’ If it exists – if it is law – then the rules have to be applied. That was the approach adopted by states when they were faced with the question of the legality of the use of force in Iraq without a further Security Council resolution after 1441. The vast majority took the view that the war was illegal and a small number took the opposite view (sometimes in difficult political circumstances). In his legal advice to the British prime minister, the attorney general went through a balanced but anguished assessment of the competing arguments, concluding that ‘a “reasonable case” does not mean that if the matter ever came before a court I would be confident that the court would agree with the view’ (advice of 7 March 2003, paragraph 30; it became public in April 2005, after War Law was published). Yet Byers seems not to want to go even the limited distance travelled by the attorney general, or to move in the opposite direction. Such hesitation tends to undermine the force of his general conclusions, with which I agree, concerning the relevance of international law and the reasons that states – even the most powerful – have a political interest in compliance.

There are other respects in which the force of War Law’s arguments is blunted, particularly in its treatment of the US. Even within the Bush administration there are competing views about the nature and extent of the US’s engagement with its international obligations. Many associated with the administration are not ‘rule-twisting megalomaniacs’ and have bent over backwards to do the right thing. They appear now to be in the ascendancy, as the price of not complying with international law becomes ever more clear. Similarly, the Foreign Office advisers who gave independent legal advice on Iraq cannot be criticised for remaining in place after the politicians decided to adopt a different course. It is not appropriate for Byers to address caustic comments towards one individual – the then Foreign Office legal adviser Michael Wood – who gave rather clearer (and more correct) views on Iraq and Resolution 1441 than those Byers puts forward himself.

There is a need for greater realism about international institutions. The future developments and application of rules in these areas is bound to be affected by issues ranging from technological developments to the perceived effectiveness of those institutions. It is not sensible to assume that the Security Council would definitely act if provided with clear evidence of an imminent biological, chemical or nuclear attack. No state can rely completely on that, especially given what we have learned about the credibility of intelligence and the political fallout associated with the use of a veto by a permanent member of the Security Council. The rules must be treated as sufficiently flexible to allow states to exercise their right of self-defence, if indeed the intelligence is credible and there is a real threat of attack.

Now that international rules affect an ever growing number of areas of law, the way in which they are made, and may be applied by international courts, can be a matter of concern. It is no answer to this to point, as Byers does, to an analogous ‘democratic deficit’ in the US. Treaties are debated very fully and democratically in Congress, and once the US has signed up to them, it has an admirable record of compliance which the rest of the world would do well to match. It is important to distinguish between the US (including its courts and its legislature) and the Bush administration.

A reader of these two books might conclude that the post-1945 project is now in tatters. Yet that is not the case: the great majority of rules work well and are generally followed. The US continues to play an important and often positive role, and there are some signs that in its dying days the Bush administration is changing course. In a curious way the recent assault on the rules may actually have strengthened them, as the price of non-compliance emerges. There may yet be a ‘1945 moment’ that leads to a restructuring of the global legal order, but I suspect this is not it.